Turning characteristics of KVLCC2 in regular head and beam waves

Abstract

Free-running tests for 1/100 scaled KVLCC2 model ship are performed in regular waves and its turning characteristics are investigated in this study. Model tests are carried out in Ocean basin of Korea Research Institute of Ships and Ocean Engineering (KRISO). Real-time motion measuring devices such as gyro, inclinometer, as well as self-propulsion and steering system are installed on the model ship. Model ship trajectories are measured by detecting the laser reflection beam from the target on the model. Wave height is fixed as 2.0 percent of model ship length, and the wave lengths are varied from 0.5 L to 1.5 L. 35 degree port and starboard turning tests are performed in regular head and port beam waves. Modelpropulsion point for the model ship speed corresponding to the full-scale service speed, 15.5 knots in calm water is fixed as 17.5 rps in all tests. There are significant differences in the drifts of trajectories depending on the wave length. The effects of variation of speeds and yaw rates on the drifts of trajectories are analyzed. Although initial turning trajectories and speeds in beam waves are different from those in head waves, the drifts of trajectories show similar tendencies in head and beam waves during steady turns. In some cases, the wave heights are varied in range of 1.0 to 2.0 percent of ship length. The trajectories are compared to each other and the drifts of trajectories are analyzed.